RU2742774C2 - Coating agent and coatings obtained therefrom with improved resistance to contamination and self-cleaning properties and use thereof - Google Patents

Abstract

FIELD: coating agents.

SUBSTANCE: present invention relates to a non-aqueous coating agent comprising at least one compound which contains hydroxyl groups, at least one compound which includes isocyanate groups, having free or blocked isocyanate and silane groups, at least one catalyst for crosslinking silane groups, and at least one siloxane with alkoxysilyl functional groups.

EFFECT: coatings obtained using the coating agent according to the invention provide excellent resistance to dirt and good self-cleaning properties, while maintaining a good appearance, in particular, good resistance to turbidity and resistance to corrosion, even after exposure to atmospheric effects.

18 cl, 6 tbl

Description

The present invention relates to a non-aqueous coating agent comprising at least one compound comprising hydroxyl groups, at least one compound comprising isocyanate groups having free or blocked isocyanate and silane groups, at least one catalyst for crosslinking silane groups, and at least one siloxane with alkoxysilyl functional groups.

State of the art

Coating agents containing compounds (A), which include hydroxyl groups, as well as compounds (B), which include isocyanate groups and silane groups, where compounds (B) are based on known isocyanates, preferably on biuret dimers and isocyanurate trimers of diisocyanates, in particular hexamethylene diisocyanate, known from WO 08/74491, from WO 08/74490, from WO 08/74489, from WO 09/077181 and from WO 10/149236. These coating agents have the advantage over their traditional polyurethane counterparts in that they have significantly improved scratch resistance combined with good weather resistance. The grindability and polishability of the coatings obtained from said coating agents have been optimized in WO 2012/168014 and WO 2012/059611. However, there are no details and no challenges regarding the resistance to contamination and / or the (self-) cleaning properties of coatings obtained from coating compositions, in particular after exposure to the weather.

Known from WO 07/033786 are coating agents which, in addition to phosphonic diesters and diphosphonic diesters as catalyst (A), contain silane-containing mixtures (B), such as, for example, a mixture of isocyanate-free reaction product ( B1) hexamethylene diisocyanate isocyanurate with N, N-bis (3-trimethoxysilylpropan-1-yl) amine, and isocyanate-free reaction product (B2) isophorone diisocyanate isocyanurate with N- (3-trimethoxysilyl) -N-1-yl n-butylamine, and optionally, as additional auxiliary agents (B) polyacrylate resins or other binders and crosslinking agents. The coatings obtained from said coating agents, after they have hardened, again have good scratch resistance combined with high resistance to chemicals and environmental influences, but the weather resistance needs to be improved and obtainable coatings are very fragile. At the same time, the data and objectives with respect to resistance to pollution and (self-cleaning properties of the resulting coatings are not indicated.

The agents described in WO 2001/98393 are two-component coating agents containing a polyol as a binder component and as a crosslinking component containing a mixture of a polyisocyanate (A) and a silane oligomer (B), wherein it contains at least two isocyanate groups and additionally alkoxysilane groups, preferably bisalkoxysilane groups, and which is obtained by reacting a polyisocyanate (PI) with alkoxysilylamines, preferably bisalkoxysilylamines, in particular bis (3-propyltrimethoxysilyl) amine. As a polyisocyanate (A), as well as a polyisocyanate (PI) to obtain component (B), preference is given to the use of hexamethylene diisocyanate and isophorone diisocyanate, as well as their biuret and isocyanurate. These coating agents are used, in particular, as a primer and are optimized for adhesion to metal substrates, preferably aluminum substrates. Here again, there is no reference to the resistance to contamination and the (self-) cleaning properties of the resulting coatings.

Moreover, water-repellent coating agents based on (meth) acrylates are known, for example, from EP 0348946 A1, from WO 99/26994, and from US 2012/0302693. In these coating compositions, fluorine-containing additives or fluorine-containing functional groups are incorporated into the polymeric structure, resulting in water repellency and improved dirt pickup and / or cleaning properties. However, there is no disclosure of coatings that combine improved (self-) cleaning properties with good appearance, in particular after exposure to weathering. Siloxanes are used, if they are used at all, only in the form of dimethylpolysiloxane as a flow control additive.

Cover varnishes are known from EP 1295914, the coating of which has improved water and oil repellency properties, and at the same time retains acid resistance. In this regard, coating varnish materials are described that contain acrylates containing hydroxyl and epoxy groups, resins based on polyesters, which have a high acid number of 120-200 mg KOH / g, while the acrylate includes alkoxysilyl groups, and at the same time the acrylate resin includes alkoxysilyl groups and dimethylpolysiloxane side chains, and the resulting coating has a Tg ranging between 100 and 120 ° C. However, it has not disclosed weather resistant coatings that have reduced contamination and improved (self-) cleaning properties.

US 9120916 B1 describes coating agents that result in improved stain resistance on substrates by applying a two-component coating agent containing acrylates having hydroxyl and polydialkylsiloxane groups, as well as chemically bonded Si particles, functionalized ethylenically unsaturated compounds. Additionally, polydialkylsiloxane functional groups are present in the curing component in US 9187670 B1. However, coatings that have improved dirt resistance and improved (self-) cleaning properties, even after external weathering, have not been disclosed.

From WO 2011/056555 A1, scratch-resistant coating agents are known composed of components with alkoxysilane groups (A), polysiloxanes containing functional groups (B) and components (C) that are reactive with respect to functional groups (B ). However, no contamination resistance and / or (self-) cleaning properties of the resulting coatings are disclosed.

The use of (fluorine-free) highly branched polyalkoxysiloxanes as additives in coating compositions for the purpose of improved (self-) cleaning properties and reduced surface contamination of coatings is known from WO 2014/187972 A1. However, no weather resistant coatings are disclosed herein.

A task

For this reason, the problem to be solved by the present invention is to provide coating agents, in particular for serial painting of a vehicle by the OEM (original equipment manufacturer - manufacturer) and car paintwork during repair work, which also provide coatings that have improved resistance to pollution and (self-) cleaning properties, in particular after exposure to weathering.

Moreover, the coating agents must meet the requirements that are usually imposed on the transparent lacquer layer in serial paintwork of the vehicle with PPO and paintwork of the car during repair work.

The solution of the problem

In light of the solution to the above problem, a non-aqueous coating agent was obtained containing:

(A) at least one compound (A) containing hydroxyl groups, having a hydroxyl number of 100-400 mg KOH / g, and a Tg> -35 ° C, which is present in an amount that is not less than 25 wt. %, based on the content of the binder in the coating agent,

(B) at least one compound (B) containing isocyanate groups having free or blocked isocyanate groups, wherein component (B) contains at least one structural unit of formula (I)

and / or at least one structural unit of the formula (II)

Where

R = hydrogen, alkyl, cycloalkyl, aryl, or aralkyl, while it is possible that the carbon chain will be interrupted by non-adjacent oxygen, sulfur, or NRa groups, where Ra = alkyl, cycloalkyl, aryl, or aralkyl,

R '= hydrogen, alkyl, or cycloalkyl, while it is possible that the carbon chain will be interrupted by non-adjacent oxygen, sulfur, or NRa groups,

X, X '= unbranched and / or branched alkylene or cycloalkylene radical having from 1 to 20 carbon atoms,

R '' = alkyl, cycloalkyl, aryl, or aralkyl, whereby it is possible for the carbon chain to be interrupted by non-adjacent oxygen, sulfur, or NRa groups,

n = 0-2, m = 0-2, m + n = 2, them, y = 0-2,

and

(B) at least one catalyst (B) for crosslinking silane groups,

and additionally present

(D) at least one alkoxysilyl functional siloxane of formula (III)

wherein

A represents a group - [O-SiR ⁵ ₂ ] - and B represents a group - [O-SiR ⁶ R ⁷ ] -,

R ² , R ³ , R ⁵ , and R ^6, independently of one another, are straight-chain or branched alkyl groups having from 1 to 4 carbon atoms,

R ¹ , R ⁴ , and R ⁷ independently of each other represent a group -LR ⁸ ,

in which L = unbranched or branched divalent alkyl group, and

R ⁸ = H or -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , where R ⁹ , R ¹⁰ = a straight or branched alkyl group having from 1 to 4 carbon atoms and z = 0, 1, or 2 , preferably z = 0,

provided that at least one of the radicals R ¹ or R ⁴ and / or at least one group B is a group R ⁸ = -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z ,

x is independently an integer that ranges from 1 to 20,

y is independently an integer that ranges from 0 to 10,

and preferably x + y 20.

The new non-aqueous coating agent is also referred to as a non-aqueous coating agent in accordance with the invention. Preferred embodiments of the non-aqueous coating agent according to the invention are apparent from the description that follows and from the dependent claims.

The present invention also provides a method for producing coatings and multilayer coatings using the coating agent according to the invention, as well as the coating or multilayer coatings obtained by said method. In addition, the present invention relates to the use of a coating agent according to the invention for improving the stain resistance and (self-) cleaning properties of coatings, in particular transparent lacquers.

The coating obtained by means of the coating agent according to the invention has, in particular, excellent stain resistance and good (self-) cleaning properties, while at the same time retains a good appearance, in particular good haze resistance and stability. to corrosion, even after exposure to the weather.

Description of the invention

Coating agent according to the invention

The coating agent according to the invention is non-aqueous. This is known to mean that, for the purposes of the present invention, the coating agents contain organic solvents or are formulated as water-free systems. In any case, the coating agent contains only minor amounts of water, and preferably does not contain water (not containing water). Especially preferably, the coating agent contains less than 5 wt. % water, preferably less than 2.5 wt. % of water, based on the total weight of the coating agent. For this reason, water is preferably used, if it is used at all, only, for example, by using conventional coating additives in the coating agent.

Compound (A) containing hydroxyl groups

The non-aqueous coating agent contains at least one compound (A) containing hydroxyl groups, having a hydroxyl number of 100-400 mg KOH / g, and a Tg> -35 ° C, which is present in an amount that is not less than 25 wt. %, relative to the content of the binder in the coating agent.

As the compound (A) containing hydroxyl groups, it is possible to use any compounds known in this sense to the person skilled in the art. Preferred compounds (A) are compounds that have on average at least 2 hydroxyl groups per molecule and are oligomeric and / or polymeric. It is also possible to use mixtures of different oligomeric and / or polymeric compounds containing hydroxyl groups as compound (A).

Preferred oligomeric and / or polymeric compounds (A) containing hydroxyl groups have weight average molecular weights Mw> 500 daltons, as determined by gel permeation chromatography (GPC), compared to a polystrile standard, preferably have weight average molecular weights found in the range between 800 and 100,000 daltons, in particular in the range between 1,000 and 50,000 daltons.

Particularly preferred are polyester polyols, polyurethane polyols, polysiloxane polyols, polyacrylate polyols and / or polymethacrylate polyols, as well as copolymers thereof, hereinafter referred to as poly (meth) acrylate polyols.

Compounds (A) containing hydroxyl groups have a hydroxyl number (number of hydroxyl groups) of 100 to 400 mg KOH / g, preferably 150-250 KOH / g. The number of hydroxyl groups refers to the amount of mg of potassium hydroxide which is equivalent to the amount of acetic acid bound by 1 g of solid during acetylation. To determine it, the sample is boiled with acetic anhydride-pyridine, and the resulting acid is titrated with a potassium hydroxide solution (DIN 53240-2).

The glass transition temperature Tg of the compounds (A) containing hydroxyl groups is above -35 ° C, preferably from -35 to 100 ° C, more preferably from -30 ° C to 80 ° C (as measured by DSC {differential scanning calorimetry) in accordance with DIN EN ISO 11357-2; see also the Examples section).

Moreover, the compounds (A) containing hydroxyl groups preferably have an acid number of 0-30 mg KOH / g. The acid number in this application indicates the amount of mg of potassium hydroxide consumed during the neutralization of 1 g of the corresponding compound (DIN EN ISO 2114).

Suitable polyester polyols are described, for example, in EP 0 994 117 A1 and EP 1 273 640 A1. Polyurethane polyols are preferably prepared by reacting polyester polyol prepolymers with suitable di- or polyisocyanates and are described, for example, in EP 273 640 A1. Suitable polysiloxane polyols are described, for example, in WO 01/09260, while the polysiloxane polyols referred to in this document can preferably be used in combination with other polyols, in particular with polyols having relatively high glass transition temperatures.

Very preferably, component (A) contains one or more poly (meth) acrylate polyols. Together with the poly (meth) acrylate polyol or polyols, additional oligomeric and / or polymeric compounds containing polyhydroxyl groups can be used, examples of which are polyester polyols, polyurethane polyols and polysiloxane polyols, especially polyester polyols.

Poly (meth) acrylate polyols, which are particularly preferred according to the invention, are mainly copolymers, and preferably have a weight-average molecular weight M _w in the range between 1000 and 20,000 daltons, in particular between 1500 and 10,000 daltons, as determined in each case by gel permeation chromatography (GPC) versus a polystrile standard.

The glass transition temperature Tg of particularly preferred poly (meth) acrylate polyols is preferably -35 to 100 ° C, in particular -35 to 20 ° C (as measured by the DSC method according to DIN EN ISO 11357-2, see also (See Examples section)

Particularly preferred poly (meth) acrylate polyols have a hydroxyl group number of 100-300 mg KOH / g, in particular 150-200 mg KOH / g, and an acid number of 0-30 mg KOH / g.

The hydroxyl number (number of hydroxyl groups) and acid number are determined as described above (DIN 53240-2 and DIN EN ISO 2114).

The monomer units containing hydroxyl groups used are preferably hydroxyalkyl (meth) acrylates, such as in particular 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate 3-hydroxybutyl methacrylate and in particular 4-hydroxybutyl acrylate and / or 4-hydroxybutyl methacrylate.

Additional monomer units which are used for the poly (meth) acrylate polyols are preferably alkyl acrylates and / or alkyl methacrylates, preferably such as ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, terthacrylate butyl acrylate, iso-methacrylate, tert-acrylate butyl acrylate -butilmetakrilat, amilakrilat, amilmetakrilat, hexyl acrylate, hexyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, 3,3,5-trimetilgeksilakrilat, 3,3,5-trimetilgeksilmetakrilat, stearyl acrylate, stearyl methacrylate, lauryl acrylate or lauryl methacrylate, tsikloalkilakrilaty and / or tsikloalkilmetakrilaty such as tsiklopentilakrilat, tsiklopentilmetakrilat , isobornyl acrylate, isobornyl methacrylate, or in particular cyclohexyl acrylate and / or cyclohexyl methacrylate.

Additional monomer units that can be used for poly (meth) acrylate polyols are vinyl aromatic hydrocarbons such as vinyl toluene, alpha-methyl styrene, or in particular styrene, acrylic or methacrylic acid amides or nitriles, vinyl esters or vinyl ethers, and also, in minor amounts, in particular acrylic and / or methacrylic acid.

In an amount of at least 25 wt. %, preferably from 25 to 70 wt. %, with respect to, in each case, the content of the binder in the coating agent, the coating agents according to the invention contain at least one compound (A), which includes hydroxyl groups, having a hydroxyl number of 100-400 mg KOH / g, and Tg> -35 ° C, in particular at least one compound (A) containing hydroxyl groups having a hydroxyl number of 100-250 mg KOH / g and a Tg of -35 ° C to 100 ° C.

Particularly preferred coating agents according to the invention are agents which, in an amount of at least 25 wt. %, preferably 25-70 wt. %, with respect to, in each case, the content of the binder in the coating agent, contain at least one poly (meth) acrylate polyol (A) having a hydroxyl number of 100-300 mg KOH / g and a Tg of -35 ° C is 100 ° C, in particular at least one poly (meth) acrylate polyol (A) having a hydroxyl number of 150-200 mg KOH / g and a Tg of -35 ° C to 20 ° C.

The part of the binder referred to in this application in each case means the specified part of the coating agent before crosslinking, which is soluble in tetrahydrofuran (THF). For this purpose, a small sample (P) is weighed and dissolved in 50-100 times more THF, the insoluble constituents are removed by filtration, the THF is evaporated, and then the mass of the constituents previously dissolved in THF is determined by drying at 130 ° C for 60 minutes, evaporator cooling, and then re-weighing. The remainder corresponds to the content of the binder of the sample (P), and is recorded in wt. %.

As you know, binders are the term used for organic compounds and coating agents that are responsible for film formation. They represent the non-volatile fraction of the coating agent minus the pigments and fillers, in accordance with DIN EN ISO 4618. Then, from the coating agent, after it has been applied to a (non-uniform) substrate, a polymer film is formed, and thus the coating film or the formed coating is based on an organic polymer matrix.

Compound (B) containing isocyanate groups

The non-aqueous coating agent contains at least one defined compound (B) containing isocyanate groups having free or blocked isocyanate groups.

Di- and / or polyisocyanates, which serve as starting structures for isocyanate-containing compounds (B), preferably used in accordance with the invention, are preferably conventional substituted or unsubstituted aromatic, aliphatic, cycloaliphatic and / or heterocyclic polyisocyanates. Examples of preferred polyisocyanates are the following: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, p-phenylenediisocyanate, biphenyl diisocyanates, 3,3'-dimethyl- 4,4'-diphenylene diisocyanate, tetramethylene 1,4-diisocyanate, hexamethylene-1,6-diisocyanate, 2,2,4-trimethylhexane 1,6-diisocyanate, isophorone diisocyanate, ethylene diisocyanate, 1,12-dodecanediisocyanate, cyclobutane-1,3 -diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, methylcyclohexyl diisocyanates, hexahydrotoluene-2,4-diisocyanate, hexahydrotoluene-2,6-diisocyanate, hexahydrophenylene-1,3-diisocyanate, hexahydrophenylene-1,3-diisocyanate -diizotsianat, pergidrodifenilmetan-2,4'-diisocyanate, 4,4'-metilenditsiklogeksildiizotsianat (e.g., Desmodur ^® W from Covestro company), tetrametilksilildiizotsianaty (e.g., TMXDI ^® from American Cyanamid company), and mixtures of the aforementioned polyisocyanates. Additionally preferred polyisocyanates are isocyanurate trimers and / or allophanate dimers and / or biuret dimers and / or uretdione dimers of the above diisocyanates.

In a further embodiment, the polyisocyanates are polyisocyanate prepolymers having urethane structural units, which are obtained by reacting polyols with a stoichiometric excess of the above polyisocyanates. Prepolymers of polyisocyanates of this kind are described, for example, in US Pat. No. 4,598,131.

Particularly preferred polyisocyanate precursors for component (B) are hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-methylene dicyclohexyl diisocyanate and / or their isocyanurate trimers and / or their allophanate dimers and / or their biuret dimers and / or their dimers.

Polyisocyanates and / or their isocyanurate trimers and / or their allophanate dimers and / or their biuret dimers and / or their urethione dimers, which are used as component (B), in addition additionally contain at least one structural unit of the formula (I)

and / or at least one structural unit of the formula (II)

Where

R = hydrogen, alkyl, cycloalkyl, aryl, or aralkyl, while it is possible for the carbon chain to be interrupted by non-adjacent oxygen, sulfur, or NRa groups, where Ra = alkyl, cycloalkyl, aryl, or aralkyl,

R '= hydrogen, alkyl, or cycloalkyl, while it is possible for the carbon chain to be interrupted by non-adjacent oxygen, sulfur, or NRa groups, where Ra = alkyl, cycloalkyl, aryl, or aralkyl, preferably R' = methyl and / or ethyl,

X, X '= straight and / or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, preferably X, X' = alkylene radical having 1-4 carbon atoms,

R ″ = alkyl, cycloalkyl, aryl, or aralkyl, whereby it is possible for the carbon chain to be interrupted by non-adjacent oxygen, sulfur, or NRa groups, where Ra = alkyl, cycloalkyl, aryl, or aralkyl, preferably R ″ = alkyl radical , in particular, having 1-6 C atoms,

n = 0-2, m = 0-2, m + n = 2, them, y = 0-2.

The corresponding preferred alkoxy radicals (OR ') may be the same or different; however, critical to the structure of the radicals is how much they affect the reactivity of the hydrolysable silane groups. Preferably R 'is an alkyl radical, in particular having 1-6 C atoms. Particularly preferred are R' radicals, which increase the reactivity of the silane groups, that is, they represent good leaving groups. Accordingly, the methoxy radical is preferred over the ethoxy radical, which in turn is preferred over the propoxy radical. For this reason, it is particularly preferred that R '= ethyl and / or methyl, in particular methyl.

The reactivity of the organofunctional silanes may additionally depend on the length of the intermediates X, X 'between the silane functional group and the organic functional groups that serve to react with the constituent component to be modified, this effect being significant. In this regard, by way of example, there may be mentioned "alpha" -silanes, which are available from Wacker, in which the methylene group, instead of the propylene group present in the case of "gamma" -silanes, is between the Si atom and the functional group.

Components (B), which are preferably used in accordance with the invention, functionalized with structural units (I) and / or (II), in particular, are obtained by reaction of polyisocyanates and / or their isocyanurate trimers and / or their allophanate dimers and / or biuret dimers and / or uretdione dimers with at least one compound of formula (Ia)

and / or with at least one compound of formula (Pa)

where the substituents are as defined above.

Components (B), which are particularly preferably used in accordance with the invention, functionalized with structural units (I) and (II), are more preferably obtained by reaction of polyisocyanates and / or their isocyanurate trimers and / or their allophanate dimers and / or their biuret dimers, and / or uretdione dimers with at least one compound of formula (Ia) and with at least one compound of formula (IIa), wherein the substituents are as defined above.

Compounds (IIa) preferred according to the invention are bis (2-ethyltrimethoxysilyl) amine, bis (3-propyltrimethoxysilyl) amine, bis (4-butyltrimethoxysilyl) amine, bis (2-ethyltriethoxysilyl) amine, bis (3-propyltriethoxysilyl) ) amine and / or bis (4-butyl-triethoxysilyl) amine. Bis (3-propyltrimethoxysilyl) amine is particularly preferred. Amino silanes of this kind are available, for example, under the trade name DYNASYLAN ^® from Evonik's or Silquest ^® from the company Momentive.

Compounds (Ia) preferred according to the invention are N- (2- (trimethoxysilyl) ethyl) alkylamines, N- (3- (trimethoxysilyl) propyl) alkylamines, N- (4- (trimethoxysilyl) butyl) alkylamines, N - (2- (triethoxysilyl) ethyl) alkylamines, N- (3- (triethoxysilyl) propyl) -alkylamines and / or N- (4- (triethoxysilyl) butyl) alkylamines. N- (3- (trimethoxysilyl) propyl) butylamine is particularly preferred. Aminosilanes of this type are available, for example under the tradename DYNASYLAN ^® from Evonik company or Silquest ^® from the company Momentive.

Preferably, in component (B) in the range between 10 and 90 mol. %, preferably in the range between 20 and 80 mol. %, more preferably more than 30 and less than 70 mol. %, and very preferably in the range between 31 and 50 mol. % of the initially present isocyanate groups were reacted to give structural units (I) and / or (II).

The number of structural units (I) in compound (B) is preferably in the range between 5 and 70 mol. %, more preferably in the range between 8 and 50 mol. %, very preferably in the range between 9 and 40 mol. %, based in each case, the total amount of structural units (I) plus (II), and the total number of structural units (II) in component (B) is preferably in the range between 95 and 30 mol. %, more preferably in the range between 92 and 50 mol. %, and very preferably in the range between 91 and 60 mol. %, based in each case, the total amount of structural links (I) plus (II).

Moreover, it is especially preferred when more than 25 mol. % and less than 36 mol. %, preferably in the range between 26 and 35 mol. %, isocyanate groups initially present in compound (B) containing isocyanate groups undergo a reaction, as a result of which bisilane structural units (II) are obtained.

Particularly preferred coating agents are obtained when, in compound (B), the total number of structural units (I) is between 9 and 40 mol%. % and the total number of structural units (II) is in the range between 91 and 60 mol. %, based in each case, of the total amount of structural units (I) plus (II),

and

in the range between 31 and 50 mol. % of the isocyanate groups initially present in (B) undergo a reaction, resulting in structural units (I) and (II),

and

in connection (B), in the range between 26 and 35 mol. % of the initially present isocyanate groups are reacted, resulting in structural units (II).

The reaction of the isocyanate group-containing compounds (B) with the compounds (Ia) and / or (IIa) preferably takes place under an inert gas atmosphere at temperatures of not more than 100 ° C, preferably not more than 60 ° C.

The free isocyanate groups of the isocyanate group-containing compounds B can also be used in blocked form. It is preferred when the coating agents according to the invention are used as one-component systems. For blocking, it is possible in principle to use any blocking agent that can be used for blocking polyisocyanates and which has a sufficiently low unblocking temperature. Blocking agents of this kind are well known to the person skilled in the art. Preference is given to the use of blocking agents of the type described in EP 0 626 888 A1 and EP 0 692 007 A1.

Preferred coating agents in accordance with the invention are agents that include 15 to 60 wt. %, preferably from 20 to 50 wt. % of compound (B) containing isocyanate groups, relative, in each case, to the content of the binder (for definition see above) in the coating agent.

Catalyst (B)

The coating agent according to the invention contains at least one catalyst (B) for crosslinking silane groups. Examples are metal complexes with chelating ligands based on zinc or aluminum, such as Lewis acids or titanates, as described, for example, in WO 05/03340 - however, when choosing the catalysts, it must be ensured that they do not lead to yellowing integumentary agents. Moreover, a number of catalysts, the use of which is traditional (for example, organotin compounds), are less desirable because of their toxicity.

Therefore, as the catalyst (B), it is preferable to use phosphorus catalysts, in particular, phosphorus and nitrogen catalysts. In this case, it is possible to use mixtures of two or more different catalysts (B).

Examples of suitable phosphorus catalysts (B) are substituted phosphonic diesters and diphosphonic diesters, preferably from the group consisting of acyclic phosphonic diesters, cyclic phosphonic diesters, acyclic diphosphonic diesters and cyclic diphosphonic diesters, and cyclic diphosphonic diesters. Catalysts of this kind are described, for example, in German patent application DE 102005045228 A1.

However, in particular, use is made of substituted phosphoric acid monoesters and phosphoric acid diesters, preferably from the group consisting of acyclic phosphoric acid diesters and phosphoric acid cyclic diesters, more preferably amine adducts of phosphoric acid monoesters and diesters.

As catalyst (B), it is particularly preferred to use the corresponding amine-blocked phosphoric acid esters, and among them, in particular, amine-blocked ethylhexyl phosphates and amine-blocked phenyl phosphates, very preferably amine-blocked bis (2-ethylhexyl) phosphates.

Examples of amines which block phosphoric acid esters are, in particular, tertiary amines, examples of which are bicyclic amines such as, for example, diazabicyclooctane (DABCO), diazabicyclononene (DBN), diazabicycloundecene (DBU), dimethyldodecylamine. For blocking the phosphoric acid esters, it is particularly preferred to use tertiary amines, which provide a high catalyst activity under hardening conditions at 140 ° C.

Certain amine blocked phosphoric acid catalysts are also commercially available (eg, Nacure series products from King Industries). As an example, under the name Nacure 4167, King Industries offers a particularly suitable catalyst that is based on an amine blocked partial phosphoric acid ester.

The catalysts are preferably used in proportions of 0.01-10 wt. %, more preferably in fractions of 0.1-5 wt. %, based on the content of the binder, by weight of the coating agent in accordance with the invention (for definitions, see above). The lower activity of the catalyst can be partially compensated for by correspondingly higher amounts used.

The coating compositions according to the invention can further comprise an additional amine catalyst based on a bicyclic amine, in particular an unsaturated bicyclic amine. Examples of suitable amine catalysts are 1,5-diazabicyclo [4.3.0] non-5-ene or 1,8-diazabicyclo [5.4.0] undec-7-ene.

Said amine catalysts, when used, are preferably used in proportions of 0.01-10 wt. %, more preferably in fractions of 0.1-5 wt. %, based on the content of the binder in the coating agent in accordance with the invention.

Siloxane (D) with alkoxysilyl functional groups

The non-aqueous coating agent additionally contains at least one siloxane (D) with alkoxysilyl functional groups.

Siloxanes are known to those skilled in the art. They are components derived from pure silanes (that is, from binary compounds consisting of Si and H) (derivatives of pure silanes) of the general formula R ₃ Si- [O-SiR ₂ ] _n -O-SiR ₃ , where R can represent hydrogen atoms or alkyl groups. In addition, in siloxanes, silicon atoms are bonded to their adjacent silicon atom by exactly one oxygen atom, and they contain at least one Si — O — Si bond. In the event that at least one of the hydrogen atoms is replaced by an organic radical, such as an alkyl group, they are also called organosiloxanes.

Oligomeric or polymeric organosiloxanes (siloxanes, where R ≠ H) have long Si-O backbones, and these are in turn called silicones.

In case the above-described organic radical in the organosiloxane also contains at least one alkoxysilyl group, and therefore at least one hydrogen residue in the organic radical is substituted by an alkoxysilyl group, and thus, at least proportionally, hydrogen in the derivative of pure the siloxane is substituted with an organic radical, which in turn itself contains an alkoxysilyl functional group, for the purposes of the present invention the corresponding compound is identified as an alkoxysilyl functional siloxane.

An alkoxysilyl-functional radical is a functional group that is derived from alkoxysilane, a component derived from pure silane and containing a Si — OR group. For this reason, at least one hydrogen atom of the pure silane is substituted by an alkoxy group —OR, in other words the alkyl group is attached to silicon by oxygen. Examples include mono-, di-, or trimethoxy- or -ethoxysilane.

Accordingly, siloxanes with alkoxysilyl functional groups intended for use in accordance with the invention are derivatives of a siloxane in which at least one hydrogen atom has been replaced by an organic radical, in which, in turn, at least one hydrogen residue has been replaced by an alkoxysilyl group. For this reason, an alkoxysilyl group can always be understood as a functional group of an alkyl group, which itself is attached to a siloxane structure. Thus, the alkoxysilyl group is always linked to the Si-O-Si structure via a divalent organic radical R, for example alkylene, and never directly attached to the original siloxane structure, consisting of Si-O-Si units.

The at least one alkoxysilyl-functional siloxane (D) can be straight-chain, branched, or cyclic. It is preferably unbranched.

Preferred alkoxysilyl functional siloxanes (D) are described by the following general formula (III):

wherein

A represents a group - [O-SiR ⁵ ₂ ] - and B represents a group - [O-SiR ⁵ ₂ ] -,

R ² , R ³ , R ⁵ , and R ⁶ independently of each other represent straight or branched alkyl groups having 1-4 carbon atoms,

R ¹ , R ⁴ , and R ⁷ independently of each other represent a group —LR ⁸ , in which L = a straight or branched chain divalent alkyl group and

R ⁸ = H or —Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , where R ⁹ , R ¹⁰ = a straight or branched alkyl group having 1-4 carbon atoms and z = 0, 1, or 2, preferably z = 0,

provided that at least one of the radicals R ¹ or R ⁴ and / or at least one group B contains a group R ⁸ = -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z ,

x is independently an integer that ranges from 1 to 20,

y is independently an integer that ranges from 0 to 10,

and preferably x + y 20.

For this reason, in any case, the siloxane (D) contains at least one —Si (R ⁹ ) _z (OR ¹⁰ ) _3-z group.

If y> 0, there are not only structural elements A, but also structural elements B, which are present in the polysiloxane chain. In the case when, on the other hand, y = 0, then only the elements of the structure A are present. Preferably, only the elements of the structure A are present (y = 0). More preferably y = 0 and x is a number from 6 to 14.

Siloxanes (D) with alkoxysilyl functional groups can be straight or branched, whereby the radicals R ¹ , R ⁴ and / or R ⁷ contain an alkoxysilyl group. If the alkoxysilyl groups are in the form of a radical R ⁸ = -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , where R ⁹ , R ¹⁰ = a straight or branched alkyl group having 1-4 carbon atoms and z = 0, 1 , or 2, preferably z = 0, are located in the radicals R ¹ and R ⁴ only at the ends, then the siloxane with alkoxysilyl functional groups is unbranched. On the other hand, if the radical R also contains alkoxysilyl groups, then the siloxane is branched. Preferably, the siloxane is unbranched.

The radicals R ¹ , R ⁴ , and R ⁷ are the same or different radicals, where at least one of the radicals always represents the group —LR ⁸ , in which R ⁸ corresponds to an alkoxysilyl group. Very preferably, at least one of said radicals R ¹ , R ⁴ and R ⁷ has a group —LR ⁸ , in which L is an ethylene group and R ⁸ is a trialkoxysilane group. Very preferably, L is an ethylene group and R is a trimethoxysilane or triethoxysilane group. Again, very preferably y = 0 and both end groups R ¹ and R ⁴ represent a group —LR ⁸ , in which L is an ethylene group and R ⁸ is a trimethoxysilane or triethoxysilane group. In a further highly preferred embodiment, y> 0, R ⁷ corresponds to a -LR ⁸ group in which L is an ethylene group and R is a trialkoxysilane group and R ¹ and R ⁴ are a -LR ⁸ group in which R ⁸ corresponds to a hydrogen atom.

With particular preference, the radicals R ² , R ³ , R ⁵ , R ⁶ , R ⁹ , and R ¹⁰ are the same or different alkyl radicals, and very preferably the said radicals R ² , R ³ , R ⁵ , R ⁶ , R ⁹ and R ¹⁰ are straight-chain alkyl groups having from one to four carbon atoms, and again very preferably the radicals R ² , R ³ , R ⁵ , R ⁶ , R ⁹ , and R ¹⁰ are methyl and / or ethyl radicals, in particular methyl radicals.

The coating agent according to the invention contains at least one siloxane (D) with alkoxysilyl functional groups. Accordingly, siloxanes with alkoxysilyl functional groups having an alkoxysilyl functional group in the side chain may be present along with siloxanes in which an alkoxysilyl functional group or functional groups are present or present at the ends of the siloxane chain.

Preference is given to adding to the coating agent according to the invention those siloxanes (D) with alkoxysilyl functional groups which lead to a decrease in the surface energy of the coating obtained by applying and hardening the coating agent according to the invention.

Such particularly preferred alkoxysilyl-functional siloxanes (D) are commercially available from Shin Etsu.

Coating agents in accordance with the invention preferably contain from 0.05 to 15.0 wt. %, preferably from 0.1 to 8.0 wt. %, and more preferably from 0.2 to 5.0 wt. % of at least one siloxane (D) with alkoxysilyl functional groups, while the quantitative indicators, expressed in wt. % are in each case based on the binder content (for definition, see above) in the coating agent.

Combination of components (A), (B), (C), and (D) as well as additional components of the coating agent

When the agents are one-component (1K) coating agents, then the selected compounds (B) containing isocyanate groups include free isocyanate groups blocked by blocking agents. Isocyanate groups can be blocked, for example, with substituted pyrazoles, in particular alkyl-substituted pyrazoles, such as 3-methylpyrazole, 3,5-dimethylpyrazole, 4-nitro-3,5-dimetupyrazole, 4-bromo-3,5-dimethylpyrazole, and the like. Particularly preferably, the isocyanate groups in component (B) are blocked with 3,5-dimethylpyrazole.

In the case of two-component (2K) coating agents, which are particularly preferred according to the invention, shortly before application of the coating agent, the coating component containing compound (A), which includes hydroxyl groups, as well as the additional components described below, are mixed with the additional component a coating containing compound (B), which includes isocyanate groups, as well as, optionally, additional components described below, while mixing is carried out in a conventional manner; typically, the coating component that contains compound (A) also contains catalyst (C), alkoxysilyl-functional siloxane (D), and part of the solvent. Preferably, the alkoxysilyl-functional siloxane (D) is present only in the coating component which contains the compound (A).

Compounds (A) containing hydroxyl groups, which are preferably used, are compounds which, in combination with other constituents, in particular with compounds (B) containing isocyanate groups, lead to coatings which have a glass transition temperature (Tg), which is preferably more than 70 ° C, in particular, preferably more than 75 ° C, and have a crosslinking density that is preferably more than 3.0 × 10 ⁷ Pa, in particular more than 4.0 × 10 ⁷ Pa (in for measurement methods, see Examples).

The mass fractions of compound (A) containing hydroxyl groups and compound (B) containing isocyanate groups are preferably selected so that the ratio of molar equivalents of hydroxyl groups of compound (A) to isocyanate groups of compound (B) is in the range between 1: 0 , 5 and 1: 1.5, preferably in the range between 1: 0.8 and 1: 1.2, more preferably in the range between 1: 0.9 and 1: 1.1.

Compound (A) containing hydroxyl groups and compound (B) containing isocyanate groups may be present in a suitable organic solvent.

The organic solvents (L) suitable for the coating agents according to the invention are, in particular, those solvents which in the coating agent are chemically inert towards the compounds (A) and (B) and which also do not react with (A) and / or (B) when the coating agent hardens. Examples of such solvents are aliphatic and / or aromatic hydrocarbons such as toluene, xylene, solvent naphtha, Solvesso 100 or Hydrosol® (from ARAL), ketones such as acetone, methyl ethyl ketone or methyl amyl ketone, esters such as ethyl acetate, butyl acetate , pentyl acetate or ethyl ethoxy propionate, ethers, or mixtures of the above organic solvents. Aprotic solvents or solvent mixtures preferably have a water content that is not more than 1 wt. %, more preferably not more than 0.5 wt. %, based on the organic solvent.

The coating agents according to the invention are non-aqueous coating agents and can contain organic solvents or can be formulated as solvent-free systems. Examples of suitable solvents are the organic solvents (L) already listed above. The organic solvent or solvents are or are preferably used in the coating compositions according to the invention in an amount such that the solids content of the coating means is at least 45% by weight. %, more preferably at least 55 wt. %.

In addition to compounds (A) and (B), it is possible to additionally use additional binders (E), which are preferably capable of reacting and forming support points of the polymer network with the hydroxyl groups of the compound (A) containing hydroxyl groups and / or with free isocyanate groups of compound (B) and / or with alkoxysilyl groups of compound (B) and / or compound (D). Additional binders (E) are preferably present in organic solvents.

As component (E), it is possible, for example, to use amino resins and / or epoxy resins. This refers to conventional and known amino resins, where some of their methylol and / or methoxymethyl groups can be functionalized with carbamate or allophanate groups. Crosslinkers of this type are described in EP 0245700 B1 and US 2005/0182189 A1, page 1, paragraph [0014], up to page 4, paragraph [0028], and also in the article by B. Singh et al., "Carbamylmethylated Melamines, Novel Crosslinkers for the Coatings Industry "in Advanced Organic Coatings Science and Technology Series, 1991, vol. 13, pages 193-207.

Examples of suitable amino resins (E) are all amino resins which are commonly used in the paint industry, and the properties of the resulting coating agents can be controlled by the reactivity of the amino resin. These resins are condensation products of aldehydes, in particular formaldehyde, and, for example, urea, melamine, guanamine, and benzoguanamine. The amino resins contain alcohol groups, preferably methylol groups, where, as a rule, some or preferably all of them have been esterified with alcohols. In particular, use is made of amino resins esterified with lower alcohols. Preference is given to the use of amino resins, eterifikovannyh methanol and / or ethanol and / or butanol, and examples in this case are commercially available products under the trade names ^{Cymel ®, Resimene ®, Maprenal ®} , and Luwipal ^®.

Coating agents in accordance with the invention preferably contain from 0 to 15 wt. % of one or more amino resins and / or one or more tris (alkoxycarbonylamino) triazines (D), based on the content of the binder in the coating agent according to the invention.

Moreover, the coating agent according to the invention may contain at least one conventional and known coating additive (E) other than the above components in effective amounts, the amounts indicated are amounts which are preferably up to 30% by weight. %, more preferably up to 25 wt. %, and in particular up to 20 wt. %, in each case, based on the content of the binder in the coating agent.

Examples of suitable coating additives (E) are as follows:

- in particular, UV absorbers;

- in particular, light stabilizers such as light stabilizers based on hindered amines, benzotriazoles, or oxalanilides;

- free radical scavengers;

- additives that improve sliding;

- polymerization inhibitors;

- antifoam agents;

- reactive diluents, particularly reactive diluents, which become active only in the reaction with the additional components of the components and / or water, such as, for example, Incozol ^® aspartic ethers or esters;

- wetting agents such as fluorine compounds, carboxylic acid monoesters, phosphoric acid esters, polyacrylate acids and their copolymers, or polyurethanes;

- adhesion enhancers;

- flow regulating agents;

- film-forming excipients such as cellulose derivatives;

- fillers such as, for example, nanoparticles based on silicon dioxide, aluminum oxide, or zirconium oxide; for further details, reference is made to Rompp Lexikon "Lacke und Druckfarben", Georg Thieme Verlag, Stuttgart, 1998, pages 250-252;

- additives for controlling rheological properties, such as those known from WO 94/22968, EP 0276501 A1, EP 0249201 A1 or WO 97/12945; crosslinked polymeric microparticles as disclosed, for example, in EP 0008127 A1; inorganic sheet silicates such as magnesium aluminosilicates, sodium, magnesium and sodium-magnesium-fluorine-lithium sheet silicates of the montmorillonite type; silicas such as Aerosils ^®; or synthetic polymers having ionic and / or associative groups such as poly (meth) acrylamide, poly (meth) acrylic acid, polyvinylpyrrolidone, styrene-maleic anhydride copolymers or ethylene-maleic anhydride copolymers and derivatives thereof, or hydrophobically modified ethoxylated urethanes or polyacrylates;

- combustion inhibitors.

Especially preferably, the coating agents which are used in accordance with the invention, in addition to the siloxane (D) with alkoxysilyl functional groups, as additive (E) contain less than 1 wt. %, in particular less than 0.2 wt. %, more preferably less than 0.05 wt. % of an additional (to compound (D)) hydrophobizing agent, in each case, based on the content of the binder in the coating agent, and very preferably do not contain an additional hydrophobizing agent at all, in particular, do not contain an additional hydrophobizing agent based on fluorine. Here, as is known, hydrophobizing agents are additives that significantly reduce the surface energy of the resulting coating, i.e. significantly increase the contact angle with water of the resulting hardened coating.

Particularly preferred are coating agents which contain from 25 to 70 wt. % of at least one poly (meth) acrylate polyol (A) having a hydroxyl number of 100-300 mg KOH / g and a Tg of -35 ° C - 100 ° C, based on the content of the binder in the coating material in accordance with with an invention,

20-50 wt. % of compound (B) containing isocyanate groups, based on the content of the binder in the coating agent in accordance with the invention,

0.1-5 wt. % of at least one catalyst (B), based on the content of the binder in the coating agent according to the invention,

0.2-5.0 wt. % of at least one siloxane (D) with alkoxysilyl functional groups, based on the content of the binder in the coating agent according to the invention,

0-15 wt. % of one or more amino resins and / or one or more tris (alkoxycarbonylamino) triazines (D), based on the content of the binder in the coating agent according to the invention, and

0-20 wt. % of at least one conventional and known coating additive (E), based on the binder content of the coating agent according to the invention,

the solids content of the coating agent being at least 45 wt. %, more preferably at least 55 wt. %.

Of course, in this preferred embodiment, all advantageous variations, for example with respect to components (A) to (D), described above are also to be considered advantageous. This applies to a combination of a preferred embodiment with only one, or two or more of the preferred embodiments described above.

In a further embodiment according to the invention, the coating agent according to the invention may further comprise additional pigments and / or fillers, and may serve to produce pigmented topcoats. Pigments and / or fillers that are used for these purposes are known to the person skilled in the art. Pigments are usually used in such an amount that the ratio of pigment to binder is between 0.05: 1 and 1.5: 1, in each case based on the binder content of the coating agent.

The method of obtaining coatings, and coatings obtained by the method

The present invention also provides a method for producing coatings and multilayer coatings using a coating agent according to the invention, as well as a coating or multilayer coating obtained by said method.

The application of the coating agents according to the invention can be carried out by any of the usual methods of application, such as, for example, spraying, knife-coating, brushing, pouring, dipping, soaking, sprinkling or roller painting. With regard to such application, the substrate to be coated can itself be at rest, while the application device or means are moved. Alternatively, the substrate to be coated can move while the applicator is at rest relative to the substrate or moves accordingly.

Preference is given to the use of spray application methods such as, for example, compressed air spraying, airless spraying, high speed spinning, electrostatic spray (ESTA) application, alone or in combination with hot spray application such as, for example, hot spray air.

The curing of the applied coating agents according to the invention can take place after a certain time of being left alone. The resting time serves, for example, to flatten and degass the coating film, or to evaporate volatile constituents such as solvents. The rest time can be facilitated and / or shortened by the application of higher temperatures and / or by the application of lower atmospheric humidity, provided that this does not lead to any occurrence of damage or alteration in the coating film such as premature complete crosslinking.

Thermal curing of the coating means does not have any specific characteristics from the point of view of the method, and, on the contrary, is carried out in accordance with conventional and known methods, such as heating in a chamber with forced air supply or irradiation with IR lamps. This thermal curing can also be carried out in several stages. Another preferred curing method is a near infrared (NIR) curing method.

Thermal curing is carried out advantageously at a temperature of 20-200 ° C, preferably at a temperature of 60-150 ° C for a time ranging from 1 minute to 10 hours, while longer curing times at lower temperatures can also be used. For coating automobiles and for coating plastic parts, as well as for coating commercial vehicles, temperatures which are preferably between 60 and 150 ° C are generally used. For covering a car during repair work, it is common to use lower temperatures, which are preferably in the range between 20 and 80 ° C, in particular in the range between 20 and 60 ° C.

Since the coatings according to the invention, obtained from the coating agents according to the invention, adhere excellently even to already hardened electroplated coatings, putty coats, base coats or to common and known topcoats, they are excellently suited, in addition to their use in coating vehicles PPO (production line), for paintwork of cars during repair work and / or for paintwork of hinged parts, and / or for paintwork of commercial vehicles.

The coating compositions according to the invention are excellent for forming decorative, protective, functional and / or effective coatings and finishes, in particular dirt-resistant coatings, on the body parts of vehicles (in particular, driven vehicles such as bicycles, motorcycles, buses, trucks or cars) or parts thereof; on the inner surface and outer surface of buildings; on furniture, windows and doors; on plastic molded products such as CDs and windows; on small industrial parts, containers and packaging; on household appliances; on films; on optical, electrical and mechanical components; as well as on hollow glass products and products for daily use.

For this reason, the coating agents according to the invention can, for example, be applied to an uncoated or pre-coated metal or plastic substrate treated with a putty, where the coating agents according to the invention are either colored pigments or not colored pigments, but preferably not colored pigments, and at the same time, after application and curing, transparent varnish coatings are formed. In particular, the coating agents and finishes according to the invention, in particular as a transparent lacquer coating, are used in the technologically and aesthetically demanding areas of the final coating of PPO vehicles, as well as for coating plastic parts intended for installation in or on car bodies. in particular, the bodies of top-class cars, such as, for example, in the manufacture of roofs, sunroofs, hoods, fenders, bumpers, spoilers, sills, protective strips, side trims and the like, as well as for covering a car during repair work, as well as for coating commercial vehicles such as, for example, trucks, construction vehicles with chain transmission, such as mobile cranes, forklift trucks and concrete mixers, buses, rail vehicles, floating vehicles, aircraft, as well as agricultural machinery , such as tractors and combines, and their parts.

If a metal substrate is to be coated, it is preferable to additionally coat it with a galvanic coating before applying the filler.

In the case of coating a plastic substrate, it is also preferable to pre-treat it before applying the filler. The most commonly used pre-treatment methods are flame treatment, plasma treatment, and corona treatment.

Plastic parts usually consist of ASA (styrene-acrylopitrile-acryloester), polycarbonates, blends of ASA and polycarbonates, polypropylene, polymethyl methacrylates or impact resistant polymethyl methacrylates, in particular blends of ASA and polycarbonates, preferably with a polycarbonate fraction> 50%, in particular> 40%.

ASA generally refers to high impact styrene / acrylonitrile polymers in which graft copolymers of vinyl aromatics, in particular styrene, and vinyl cyanides, in particular acrylonitrile, are present on polyalkyl acrylate rubbers in a copolymer matrix, in particular styrene and acrylonitrile.

With particular preference, the coating agents according to the invention are used in multi-stage coating processes, in particular in processes where an optionally pre-coated substrate, optionally treated with a putty, is coated first with one or more pigment-colored basecoat films and then with a film from the coating agent according to the invention, preferably as a transparent varnish film. Accordingly, the invention also provides multi-layer colored and / or effect finishes comprising at least one pigmented basecoat and at least one clear lacquer layer applied thereto, said finishes being characterized in that the clear lacquer layer has been obtained from the coating agent according to the invention. The coating agents according to the invention are preferably used for the production of clear varnishes in a multi-stage coating process in the field of final coating of APO vehicles.

In the multi-stage coating method described above, the base varnish and clear varnish can be cured together using the wet paint method, or they can be cured separately. During the wet-paint method, clearcoat is applied to the basecoat or to the topmost basecoat that has not cured. Curing is then carried out at the end, together with clear varnish. However, curing can also be carried out separately for each basecoat or clearcoat, in other words, after each application of the basecoat and clearcoat.

In this case, not only water-based basecoats can be used, but also basecoats based on organic solvents. Suitable basecoats are described, for example, in EP 0 692 007 A1 and in the documents listed here in column 3, lines 50 et seq. Preferably, the applied base coat is first dried — that is, during the evaporation phase, at least some of the organic solvent and / or water is removed from the base coat film. Drying is preferably carried out at temperatures from room temperature (20 ° C) to 80 ° C. After drying has taken place, the coating agent according to the invention is applied. The two-layer topcoat is subsequently cured, preferably under the conditions used during the final coat of PPO vehicles, at temperatures between 20 ° C and 200 ° C; preferably from 60 to 150 ° C, over a period of time ranging from 1 minute to 10 hours; in the case of temperatures used to coat a vehicle during repair work, which are generally between 20 and 80 ° C, in particular between 20 and 60 ° C, longer curing times can also be used.

In another preferred embodiment according to the invention, the coating agent according to the invention is used as a clear lacquer coating for coating plastic substrates, in particular plastic parts for indoor or outdoor installation. Also, plastic parts for indoor or outdoor installation are preferably coated during a multi-stage coating process, where optionally a pre-coated substrate or a substrate that has been pre-treated to enhance the adhesion of subsequent coatings (for example, by flame treatment, corona treatment or plasma treatment of the substrate) is first coated with a pigment-colored base lacquer film and thereafter with a coating agent film according to the invention.

Application of the coating according to the invention

In addition, the present invention relates to the use of a coating agent according to the invention for improving the stain resistance and (self-) cleaning properties of coatings, in particular clear lacquers.

For the purposes of this invention, the term "dirt resistance" refers to the ability of a coating to repel dirt. Said dirt-repellent coatings (which are also often referred to as easy-to-clean coatings) in the present invention, as in the literature, refer to coatings that have surfaces to which dirt, dust, and contaminants, such as graffiti, industrial pollution, road dirt, and natural deposits, show little or no adhesion and are therefore easy to clean.

Moreover, for the purposes of this invention, the term "(self-) cleaning property" refers to both the self-cleaning property and the surface cleaning property, here in particular the coating surface. In the case of self-cleaning, cleaning consists in simply cleaning a contaminated surface by exposing it to rain, which will certainly occur from time to time in natural conditions. In the case of actual cleaning, tools such as brushes, sponges, (high-) pressure cleaners, or other familiar cleaning equipment are also used to reduce contamination.

In general, for this purpose, the surface of the coating is provided such that its properties include water repelling properties. In other words, this means that there is a low level of wetting as a result of the extremely small interaction between the coating surface and the water to which it is exposed, thereby forming a very large contact angle between the coating surface and the water droplet lying on the coating surface. The goal is to have a minimum surface area and surface energy.

Here, surface energy (a) (abbreviated from surface energy density, surface tension) is the tension that acts on the surface and that always tends to minimize the surface area. Because of this, the surface energy is a form of work relative to the area, and its unit is N / m or J / m ² .

For a simple comparison of two different sample surfaces, the corresponding contact angle can be determined. The contact angle (surface wetting angle or contact angle) (θ) occurs between the edge of the droplet and the surface when a liquid droplet on a flat solid or liquid surface is retained in a spherical shape that is easily deformed by gravity. This is a state of minimal surface area and surface energy. The contact angle is expressed in °. Based on the contact angle, it is possible to calculate the surface energy (for the calculation method see Examples), according to Young's equation known to the person skilled in the art.

The coating obtained from the coating agent according to the invention preferably has a surface energy of <25 mJ / m ² , very preferably <22.5 mJ / m ² , and more preferably <22 mJ / m ² .

Formulating coating agents with the addition of compounds that lower surface energy often results in poor appearance of the resulting coating. The surface appearance or visual impression here includes such characteristics as color, luster, clarity, haze, surface texture, structure, orange peel defect, pinholes and / or craters. In particular, haze - a whitish coating (milky tint) and small, round depressions in the coating that remain after drying / curing are undesirable in coatings, especially in transparent lacquer coatings. Craters can extend down into the lower layers of the coating or down to the substrate, and are caused by locally limited variations in surface tension in the coating. The most common causes of cloudiness and craters are incompatibility of the components in the coating agent (binders, additives) with substances such as small oil droplets, particles or contaminants. In particular, in the case of coating agents intended to obtain a water-repellent coating, at least partial incompatibility with hydrophobic structural elements is observed.

In any case, the appearance of the coating is often cloudy as a result of at least partial incompatibility of the added components, such as, for example, hydrophobic fluorine-containing components on the one hand and binders used in the coating agent on the other hand.

The stain resistance as well as the (self-) cleaning properties of the coatings obtained from the coating compositions according to the invention were investigated by means of a stain test, by determining the value of the colorimetric lightness L *, which is known to the person skilled in the art (with respect to the measurement method, see the Examples section).

Based on the change in lightness (L * ₁ ) before contamination of the coating compared to the lightness after contamination (L * ₂ ), or after contamination and cleaning of the coating (L * ₃ ), it is possible to determine the resistance to contamination as well as the (self-) cleaning property cover. The smaller the change (delta, Δ) in lightness (ΔL *), the less contamination (ΔL * _1-2 ) and the better the surface cleaning (ΔL * _1-3 ). Therefore, ideally, if ΔL * were "zero", with the dirt not sticking at all, or cleaning the coating would restore the original value.

The fouling resistance of coatings that can be obtained from the coating agent according to the invention is expressed by changing the lightness L * before and after soiling, and is preferably ΔL * _1-2 <30, more preferably ΔL * _1-2 <25.

The (self-) cleaning property of the coatings that can be obtained from the coating composition according to the invention is expressed by changing the lightness L * before and after soiling and cleaning, and is preferably ΔL * _1-3 <20, more preferably ΔL * _{1- 3} <10, and very preferably ΔL * _1-3 <5.

Examples of

Method of measurement

Determination of solid content

Approximately 1 g of the sample is weighed into a tin lid. After adding about 3 ml of butyl acetate, the sample is dried in a drying chamber at 130 ° C for 60 minutes, cooled in an evaporator, and then weighed again. The remainder corresponds to the solids content.

Determination of the binder content

The portion of the binder (also referred to as the binder content), in each case, is the portion of the coating agent prior to crosslinking, which is soluble in tetrahydrofuran (THF). For this purpose, a small sample (P) is weighed, dissolved in 50-100 times more THF, the insoluble constituents are removed by filtration, THF is evaporated, and then the mass of the constituents previously dissolved in THF is determined by drying at 130 ° C for 60 minutes, cooling in the evaporator, and then re-weighing. The remainder corresponds to the part of the binder of the sample (P) and is expressed in wt. %.

Glass transition temperature and crosslinking density

The glass transition temperature Tg of the individual constituent components of the binder, in particular of the compound (A) containing hydroxyl groups, for the purposes of the invention is determined experimentally in accordance with DIN 51005 "Thermal analysis (TA) - terms" and in accordance with DIN EN ISO 11357-2 "Thermal Analysis - Dynamic Scanning Calorimetry (DSC)". For this purpose, a 10 mg sample is weighed into an analytical combustion boat and placed in a DSC apparatus. It is cooled to the initial temperature, after which the first and second series of measurements are carried out in a protective layer of an inert gas (N ₂ ) at a rate of 50 ml / min, with a heating rate of 10 K / min, with cooling again to the initial temperature between series of measurements. Typically, the measurement is carried out in a temperature range that is from about 50 ° C below the expected glass transition temperature to about 50 ° C above the glass transition temperature. For the purposes of the present invention, the glass transition temperature is, in accordance with DIN EN ISO 11357-2, section 10.1.2, the temperature during the second series of measurements at which half the change in specific heat is achieved (0.5 delta sr). It is determined from a DSC chart (heat flux versus temperature) and is the temperature at the midline intersection between the extrapolated baseline before and after glass transition and the measurement curve.

The glass transition temperature and crosslinking density of the coating can be determined, as is known to the person skilled in the art, by means of dynamic mechanical thermal analysis (DMTA) (according to DIN EN ISO 6721-1). Here, the physical properties of the coating are related to the crosslinked mesh structure of the coating agent.

A free film is required for measurements. It is obtained by applying a coating agent to a propylene base from which, after drying, a rectangular sample of known thickness, length, and width is taken. Said free film was cured in a DMTA V from Rheometric using a sinusoidal waveform with a frequency of 1 Hz and an amplitude of 0.2% at a heating rate of 2 ° C./minute and analyzed. The glass transition temperature (Tg) in this measurement method is recorded as the maximum value of the loss factor tan 5 from the loss modulus E '' and the storage modulus E ', and at the same time the crosslink density is indicated as the minimum value of the storage modulus E' above the Tg.

Determination of surface energy

The surface energy or surface tension of the cured coatings is determined by determining the contact angle. Liquids of known surface energies are applied dropwise in predetermined volumes to the coating and the angle between the liquid and solid surfaces is established using a Kruss DAS 10 contact angle tester. Based on this indicator, using the Kalble approximation, the surface energy is calculated. The specific approximation method to be used depends on the material from which the test sample (coating) is made.

As a measuring liquid, 5 μl of bidistilled water, 5 μl of 1,5-pentanediol, 1.5 μl of diiodomethane, 5 μl of ethylene glycol, and 5 μl of glycerol were carefully applied to the coating surface, and the resulting contact angle was recorded after 10 seconds. Measurements were carried out six times with one measurement liquid and the average is calculated.

Test for contamination and (self-) cleaning

The resistance to contamination and the (self-) cleaning properties of the coating were investigated using an in-house developed contamination test, including the test suspension. For this purpose, the colorimetric lightness L * of the sample panel was set before contamination (L * ₁ ), after contamination (L * ₂ ), and after contamination and cleaning (L * ₃ ). The difference in lightness ΔL * provides data on the resistance to dirt and the effectiveness of the (self-) cleaning properties of the coating.

At the first stage, the lightness L * (L * ₁ ) of the test panel covered with a white base coat and the test top varnish was set. All lightness measurements were made using a Byk-mac i spectrophotometer (23 mm measuring aperture) from BYK i, where the 45 ° L * value was used for data collection.

Per sample, in a circular passage (1 circular passage / s), using an Airspray air spray gun (nozzle hole 1.3 mm, compressed air 9.8 × 10 ⁴ Pa, flow rate 70 ± 3 cm ³ / min , distance from the sample 300 mm), the test suspension was applied, consisting of 0.5 wt. % carbon black (from Holbein Works), 0.2 wt. % yellow ocher (from Holbein Works), 1.3 wt. % JIS Z 8901 powder (class 8), and 98.0 wt. % water. Then the sample was dried in a drying chamber at a temperature of 90 ° C for 10 minutes. The process of applying the test suspension and the subsequent stage of drying were carried out 8 additional times, in each case 5 circular passes (1 circular pass / s) were carried out for each repetition. After that, the lightness L * of the contaminated test panel was recorded (L * ₂ ).

Using a steam-water jet (compressed air 9.8 × 10 ⁶ Pa, flow rate 70 ± 3 cm ³ / min), the panel under study was cleaned over 10 circular passes (1 circular pass / s) and dried using compressed air. The luminance L * (L * ₃ ) was set again.

The difference in lightness ΔL *, which can be composed of the individual colorimetric lightnesses L * ₁ , L * ₂ , and L * ₃ , allows comparison of resistance to contamination (ΔL * _1-2 ) as well as the efficiency of (self-) cleaning properties (ΔL * _{1 -3} ) investigated coatings.

An example of obtaining polyacrylates (A1) and polyacrylates (A2)

A 4 L stainless steel double walled chemical reactor equipped with a thermometer, paddle stirrer, 2 dropping funnels, and a reflux condenser, and heated by an oil circulation thermostat, is charged with a suitable organic solvent for polymerization. One of the dropping funnels is charged with the monomer mixture according to the data in Table 1, and the second dropping funnel is charged with an initiator solution that includes a suitable initiator (mainly peroxide). The initial charge is heated to the polymerization temperature, which is 140 ° C. When the polymerization temperature is reached, initiator feed is started first. 15 minutes after starting the initiator feed, the monomer feed is started (duration: 240 minutes). The initiator feed is adjusted so that it continues for an additional 30 minutes after the end of the monomer feed. After the end of the initiator feed, the mixture is stirred at 140 ° C for an additional 2 hours and then cooled to room temperature. The reaction mixture, using an organic solvent, is subsequently brought to the solids content shown in Table 1.

Calculation of example basecoats (S1) and (S2)

To obtain basecoats (S1) and (S2), the components listed in Table 2 were weighed in this order into a suitable vessel and mixed thoroughly with each other.

An example of the preparation of curing agents (H1) - (H4)

The protocol described below is applied to obtain curing agents (H1) - (H4). It is implemented in accordance with the publication protocol WO 2012/168014 A1, page 32, lines 4-27, in this case for the curing agent (H1). Corresponding proportions and components of curing agents (H2) - (H4) can be taken from Table 3.

The reaction vessel was charged with 39 parts by weight of trimerized hexamethyl-1,6-diisocyanate (Desmodur ^® N3300, from the company Covestro) and 36 parts by weight of butyl acetate. With cooling with a reflux condenser, a nitrogen in the protective layer, and with stirring, a mixture of 2.0 parts by weight of N- [3- (trimethoxysilyl) propyl] butylamine (Dynasylan ^® 1189 from the company Evonik) and 20 parts by weight of bis [3 - (trimethoxysilyl) propyl] amine (Dynasylan ^® 1124 from the company Evonik) was added dropwise at such a rate that the temperature did not exceed 50-60 ° C. The reaction mixture is stirred until the NCO value, determined by titration, reaches an NCO value of 5.9 wt. %, calculated theoretically for the completed reaction of amines containing silane groups. Then was added 3.0 parts by weight of trimerized isophorone diisocyanate (Desmodur ^® Z4470, 70% of solvent naphtha from Covestro Company). The resulting mixture has an NCO value of 6.1 wt. % and a theoretical solids content of 63 wt. %.

Formulation of coating agent EB1 according to the invention and comparative coating agents VB1 to VB11 and coatings according to the invention obtained therefrom according to example E1 and coatings according to comparative examples V1 to V11.

For the preparation of the coating agents, the base varnish (S1) or (S2), with or without the addition of alkoxysilyl-functional siloxane (D) or constituents according to the invention, or a comparative siloxane (hydroxyl-functional siloxane), is thoroughly mixed in a suitable vessel with one of the curing agents (H1) - (H4) in a ratio of 1: 1 (wt.: wt.).

By appropriately combining the base varnish (S1) and (S2) with one of the curing agents (H1) to (H4), coatings with high or low crosslinking densities and high or low Tg are obtained from the respective coating agents EB1 and VB1 to VB11. The coating agent EB1 according to the invention, obtained from a base varnish (S1) and a curing agent (H1), with an alkoxysilyl-functional siloxane added to the base varnish (S1), has a high crosslinking density and a high Tg. The constituent components of the coating agent are shown in Table 4.

The coatings of examples E1 and V1-V11 were prepared from coating agents EB1 and VB1-VB11 by their application, using a gravity-fed cup spray gun, on Bonder panels of 40 × 40 cm, previously coated with this curable aqueous basecoat material black color, which was then dried for 20 minutes at a temperature of 140 ° C, with a target dry film thickness of 35-45 microns.

The surface of the coatings was evaluated by measuring gloss at an angle of 20 ° using a commercially available gloss meter, as well as by visual inspection for defects (eg craters) and visual inspection.

The scratch resistance of the dried surfaces of the resulting coatings was determined by using a coating abrasion tester in accordance with EN ISO 105-X12 with 10 double abrasions and an applied force of 9 N using 9 μm sandpaper (3M ™ Wetordry ™ 281Q ), followed by determination of the residual gloss at an angle of 20 ° using a commercially available gloss meter, without recalculation.

The resistance of the coating to cracking and / or peeling from the metal substrate is determined by a stretch test in accordance with DIN EN ISO 1520 and is thus a measure of the flexibility of the coating. The penetration depth is expressed in mm and in the PPO sector must be above 6 mm.

The stain resistance and the (self-) cleaning properties as well as the surface energy of the coatings were determined in the manner described above. It also provides data on the change in the colorimetric lightness L * ₁ before pollution, compared with the lightness L * ₂ after pollution (ΔL * _1-2 ), as well as changes in the colorimetric lightness L * ₁ before pollution, compared to the lightness L * ₃ ( ΔL * _1-3 ) previously soiled coating, subsequently cleaned with a steam jet.

The test results for coatings E1 and V1 - V11 are shown in Table 5.

Additionally, after exposure to weathering, dirt resistance and (self-) cleaning properties, as well as surface energy of examples with high Tg and high crosslinking density (E1, V1, and V2) were investigated. For this purpose, sample panels with coatings E1, V1, and V2 were weathered in an open position (outdoor weathering) at an angle of 5 ° for 4 months. Then, for these sample panels, the stain resistance, (self-) cleaning properties, and surface energy tests were performed again. The results are shown in Table 6.

The results emphasize that only the EB1 coating agent according to the invention produces an E1 coating that has excellent stain resistance, good (self-) cleaning properties even after exposure to weathering, and good flexibility, without any damage to scratch resistance or the visual impression provided by the coating.

Surprisingly, it has been found that the overall reduction in surface energy is not sufficient to obtain good pollution resistance like E1, even after being exposed to the weather. In fact, as demonstrated by the stain resistance of comparative coatings V4, V7, and V10 with alkoxysilyl-functional siloxane or comparative coatings V2, V5, V8, and V11 with hydroxyl-functional siloxane, it is just that the reduction in surface energy of the coating is not sufficient to obtain excellent stain resistance and (self-) cleaning properties such as E1.

In terms of resistance to pollution, in other words, comparing the lightness L * before and after pollution (ΔL * _1-2 ), a significantly better effect is evident for coatings modified with siloxanes with alkoxysilyl functional groups (Table 5, E1, V4, V7, V10 ), compared to coatings that have been modified with hydroxyl-functional siloxanes (Table 5, V2, V5, V8, V11), and in particular compared to unmodified coatings (Table 5, V1, V3, V6, V9).

In addition, it is evident that only high crosslinking density and high Tg, with or without added siloxane not in accordance with the invention, are not sufficient to achieve excellent results of the example in accordance with the invention (compare example E1 with V1 and V2, table 5 , table 6).

Thus, based on all the examples, it is evident that only the combination of the addition of a siloxane with alkoxysilyl functional groups and a sufficiently high fraction of binders with a high Tg leads to the production of coating agents and coatings which, in addition to the requirements in principle for clearcoats, also have excellent resistance to contamination.

The (self-) cleaning properties of the E1 coating, expressed by the value (ΔL * _1-3 ), are also excellent, and again, very good results have been obtained for coatings that have high Tg and low crosslink density, or low Tg with high crosslinking density (compare table 5, V7 and V10). However, these coatings exhibit resistance to pollution, which, in fact, deserves improvement. In example E1 according to the invention, the difference in lightness before and after cleaning (ΔL * _1-3 ) is actually negative, which suggests that the sample panel had a higher lightness after cleaning than before soiling. This difference may indicate slight contamination of the panel sample, such as dust or fingerprints, prior to intentional contamination of the panel sample.

Only the E1 coating according to the invention retains - even after exposure to weathering - excellent resistance to pollution and good (self-) cleaning properties, which, although slightly lower than before exposure to weathering, are nevertheless significantly ahead of comparative coatings. in terms of quality, in particular with regard to pollution. In contrast, the advantageous properties of a hydroxyl-functional siloxane not in accordance with the invention in terms of resistance to contamination and (self-) cleaning, as compared to unmodified coatings, are lost after exposure to weathering (compare table 6, V1 and V2).

Claims (50)

1. A non-aqueous coating agent containing (A) at least one compound (A), which includes hydroxyl groups, having a hydroxyl number of 100-400 mg KOH / g, and a Tg greater than -35 ° C, which is present in an amount of at least 25 wt. %, relative to the content of the binder in the coating agent, (B) at least one compound (B) which includes isocyanate groups having free or blocked isocyanate groups, wherein component (B) contains at least one structural unit of formula (I)

and / or at least one structural unit of the formula (II)

Where R = alkyl, R '= an alkyl radical having from 1 to 6 carbon atoms, X, X '= straight and / or branched alkylene radical having from 1 to 4 carbon atoms, R '' = an alkyl radical having from 1 to 6 carbon atoms, n = 0-2, m = 0-2, m + n = 2, and x, y = 0-2, and (B) at least one catalyst (B) for crosslinking silane groups, where additionally present (D) at least one alkoxysilyl functional siloxane of formula (III)

Where A represents a group - [O-SiR ⁵ ₂ ] - and B represents a group - [O-SiR ⁶ R ⁷ ] -, R ² , R ³ , R ⁵ , and R ⁶ independently of one another represent straight or branched alkyl groups having from 1 to 4 carbon atoms, R ¹ , R ⁴ , and R ⁷ independently of each other represent a group -LR ⁸ , where L = unbranched or branched divalent alkyl group and R ⁸ = H or -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , where R ⁹ , R ¹⁰ = a straight or branched alkyl group having from 1 to 4 carbon atoms and z = 0, 1, or 2 , provided that at least one of the radicals R ¹ or R ⁴ and / or at least one group B contains a group R ⁸ = -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , x is independently an integer that ranges from 1 to 20, y is independently an integer that ranges from 0 to 10. 2. The covering agent according to claim 1, characterized in that in the formula (III) x + y is less than or equal to 20, and z = 0. 3. The coating agent according to claim 1 or 2, characterized in that it is a two-component coating agent, and the siloxane (D) with alkoxysilyl functional groups is contained in the coating agent component which contains compound (A). 4. Covering agent according to any one of paragraphs. 1-3, characterized in that R ² , R ³ , and R ⁵ independently of each other represent methyl and / or ethyl, preferably methyl, R ¹ and R ⁴ independently of each other represent a group -LR ⁸ , where L = unbranched or branched divalent alkyl group, preferably ethylene, and R ⁸ = -Si (R ⁹ ) _z (OR ¹⁰ ) _3-z , where R ⁹ , R ¹⁰ = unbranched or branched alkyl group having from 1 to 4 carbon atoms, and z = 0, 1, or 2, preferably z = 0, and y = 0. 5. Covering agent according to any one of paragraphs. 1-4, characterized in that it does not contain a fluorine-containing compound, which leads to hydrophobization of the coating obtained therefrom. 6. Covering agent according to any one of paragraphs. 1-5, characterized in that the compound (A), which includes polyhydroxyl groups, is at least one poly (meth) acrylate resin having a hydroxyl number of 100-300 mg KOH / g, preferably 150-200 mg KOH / g, and a glass transition temperature of -35-100 ° C, in particular of -35-20 ° C (measured by means of DSC in accordance with DIN EN ISO 11357-2). 7. Covering agent according to any one of paragraphs. 1-6, characterized in that it contains at least one catalyst (B), which includes phosphorus and nitrogen. 8. Covering agent according to any one of paragraphs. 1-7, characterized in that the compound (B) was obtained by reacting polyisocyanates and / or their isocyanurate trimers and / or their allophanate dimers and / or their biuret dimers and / or uretdione dimers with at least one compound of the formula (Ia)

and / or at least one compound of formula (IIa)

where substituents have the definition specified in clause 1. 9. A method of obtaining coatings by applying to an optionally pre-coated base of the coating agent according to any one of claims. 1-8. 10. The method according to claim 9, characterized in that it is used to obtain a coating, in particular a transparent lacquer coating intended for serial painting of cars, paintwork of hinged parts of a car and / or commercial vehicles, and for paintwork of cars during repair works. 11. The method according to claim 9 or 10, characterized in that the base varnish colored with the pigment and subsequently the coating agent according to any one of claims. 1-8 are applied to an optionally pretreated and optionally precoated substrate. 12. The method according to any one of claims. 9-11, characterized in that after applying the pigment-colored base varnish layer, the applied base varnish is first dried at temperatures ranging from 20-80 ° C, and, after applying the coating agent according to any one of claims. 1-8 are cured at temperatures of 20-200 ° C, preferably 60-150 ° C, for a time ranging from one minute to 10 hours. 13. The use of a coating agent according to any one of paragraphs. 1-8 to improve stain resistance and (self-) cleaning properties of coatings. 14. Use according to claim 13, characterized in that said coatings are transparent varnish coatings. 15. The coating obtained by the method according to any one of paragraphs. 9-12. 16. The coating according to claim 15, characterized in that it has a glass transition temperature (Tg) of more than 70 ° C and a crosslinking density of more than 3.0 × 10 ⁷ Pa. 17. A coating according to claim 15 or 16, characterized in that it has a resistance to contamination of ΔL * _1-2 <30, preferably ΔL * _1-2 <25, where ΔL * _1-2 determines the difference in the colorimetric lightness value L * before (L * ₁ ) and after (L * ₂ ) contamination of the sample panel on which the coating agent was applied and subsequently cured according to any one of claims. 1-8. 18. Multilayer effect and / or color coating containing at least one pigment-colored base varnish and at least one transparent varnish layer located on it, characterized in that the transparent varnish layer was obtained from the coating agent according to any one of claims. 1-8.